Tetrahydropyran compound



Patented Jan. 20, 1948 tlicUiiitedfstafics 'iifi'fimerica as represcntedc'by the Secretary of agriculture No, Drawing, application October 4,. 44,, Ser al a- D v ed; n his applieat'ion April 25 1947, Se'riaf NO; 743590?!" 110mm. ((31. acc ses) (Gran-ted una euw act of March 3; I883, as

m ed. April 3 1928; 0-

ll a p i i ism de und r t e a t Match. 3-,. -1-8 3;.asamended by ea t of ar lz. 3d,, 1923, and the invention herein. described, it patented, may be manufactured and used byorfor the Government; oi the, United Statesof Ameri go er menta p nq t t payment to me. of anyroyalty thereon.

This application is a division of my copen-ding. apn ijcat en e pat nt. ematN 557215, fi e October 4, 1944, now Patent No. 2,421,570, issued June 3, 1947,

This invention relates to insecticidal compositions containing pyrethrum and has for its object the provision of an improved composition of this type. This invention further relates to the synthesis of a new compound, namely, alpha-(3,4- methylenedioxyphenyl)tetrahydropyran, which is particularly useful when employed in conjunction with pyrethrins because of the resulting synergistic action, and also when employed as a solvent.

Insecticidal compositions containing pyrethrum are widely used to combat insect pests, such as flies, mosquitoes, gnats, and the like. Frequently, the pyrethrum is employed in a solvent of the hydrocarbon or mineral 011 type, such as odorless kerosene, naphtha, and so forth. Also,

it is employed in a solvent of liquefied gases, such as dichlorodifiuoromethane, methyl chloride, and so forth, While these insecticidal compositions have good toxic properties and are well suited for the control f household insects and the like, they are expensive.

I have found that a. new compound, namely, alpha (3,4 methylenedioxyphenyl) tetrahydropyran, represented by Formula I,

Formula I while possessing little or no insecticidal properties in itself, increases the toxicity of the pyrethrins to a decidedly advantageous extent. Thus I have found that alpha-(3,4-methylenedioxyphenyl) tetrahydropyran, when incorporated with the pyrethrins in an appropriate solvent, yields an insecticidal composition which is more effective against the ordinary housefly than can be accounted for on the basis of the pyrethrin and alpha- (3,4-methylenedioxyphenyl) tetrahydropyran content. Also, I have found that alpha- (3,4 methylienedioxyphenylitetrahydropyran .is se d so ent or d cf'h m ii nyltric mmeth arias, and in p eu'eua pn'r; which is lmownt'o; be toidfcto, household} insects',. but. which is insoluble in certain liquefied gases, such. as dichlorcdifiuoromethana, This, solvent action is so..great that.alpha ('3,4rinethylenedloxyphenyl).- tetrahydi'opyran may be used to keep. dichloroie diphenyltrichlorQfithane. in, solution. in the liquefied gas either with or without the pyrethrins depending on the purpose of the insecticide.

I prefer as the insecticidal composition a comoination of alpha-(3,4-methylenedioxyphenyl)- tetrahydropyran and the pyrethrins in either F odorless kerosene or dichlorodifiuoromethane.

However, it do not restrict my invention to this.

composition and. the new insecticidal ingredients may be used in other solvents and in combination with other insecticides, such as organic thiocyanates, rotenone, dcrris, lonchocarpus, and the like.

Alpha- (3,4-methylenedioxyphenyl) tetrahydropyran, a new compound, may be prepared by the following procedure:

The sodium compound of beta-hydroxy-beta- (3,4-methylenedioxyphenyl) acrylic ethyl ester (Formula II) is caused to react with trimethylenebromide, as illustrated below, to furnish the ethyl ester of 2,3-dihydro-6-(3,4-methylenedioxyphenyl) -1,4-pyran-5-carboxylic acid (Formula III) Formula II 2NaBr Ha Cans-( siilm hydroxide to the potassium salt of the corresponding acid which is obtained on addition of hydrochloric acid. The free-acid, on heating;

loses carbon dioxidev to furnish'2,-3- dihydro- 6- (3,4-methylenedioxyphenyl) -l,4-pyran (Formula IVLWhich is Formula IV This is then reduced with hydrogen in the presence of a platinum catalyst in a conventional manner to alpha-(3,4-methylenedioxyphenyll- 4 the above compound alone gave a 4 percent kill of housefiies in 48 hours.

. 2. A refined kerosene solution containing .05 percent of pyrethrins alone gave. a kill of 17 percent in 48 hours.

3. A refined kerosene solution containing 1 percent of the above new compound and, in addition, .05 percent of pyrethrins gave a kill of 99 diluted pyrethrin solution. This killing power is greater'than that of the average commercial fly spray which contains twice the amount of pyrethrins used in the above test. The result is a considerable saving of pyrethrins.

v The above example is by illustration only and the amount and proportion of alpha-(3,4- methylenedioxyphenyl)tetrahydropyran and of the pyrethrins may be varied over a wide range from 0.05 to 1 part by weight of pyrethrins, from 1 to 20 parts by weight of alpha-(B/i-methylenedioxyphenyl) tetrahydropyran, and from 98.95 to '79 parts by weight of kerosene.

Having thus described my invention, I claim:

Alpha- (3,4-methylenedioxyphenyl) tetrahydropyran.

FREDERICK B. LA FORGE. 

